An image forming apparatus such as a printer, a facsimile machine, or a copying machine forms an image including a character or a symbol on a recording medium such as a paper sheet, a cloth or an OHP sheet based on image information, wherein it may be possible to form a high resolution image on a plane paper sheet at a high speed, and therefore, an electrophotography-type image forming apparatus has been used widely. Because the speed of fixation is high and the quality of a fixed image is high in such an electrophotography-type image forming apparatus, a thermal fixation method for fixing a toner on a recording medium by heating and melting the toner on the recording medium and pressurizing the melted toner has been used widely. However, about a half or more of an electrical power consumption is consumed for heating a toner in such an electrophotography-type image forming apparatus.
Meanwhile, a fixation device with a low electric power consumption (for energy-saving), that is, a non-heating fixation method for fixing a toner on a recording medium without heating it has been desired from the viewpoint of recent measures to address environmental issues.
Japanese Patent Application No. 2007-219105 discloses a method for fixing a resin fine particle on a medium by producing a fixation fluid in a foam-like shape, controlling a film thickness of the produced foam-like fixation fluid, and applying it on the resin fine particle on the medium. Then, the fixation fluid contains a softening agent for softening a resin fine particle containing a resin by dissolving or swelling at least a portion of the resin, a foaming agent, and a bubble-increasing agent. For the foaming agent, alkali soaps of higher fatty acid, such as sodium stearate, sodium palmitate, and sodium myristate are illustrated. Furthermore, for the bubble increasing agent, fatty acid akanol amide-type nonionic surfactants such as coconut oil fatty acid diethanol amides, coconut oil fatty acid monoethanol amides, and lauric acid isopropanol amide are illustrated.
In a practical example of Japanese Patent Application No. 2007-219105, triethanolamine as a pH adjustor is used to reduce the alkalinity of a fixation fluid in order to improve the foaming property of a foaming agent, and if an aliphatic ester is used as a softening agent, there may be a problem such that the aliphatic ester may readily be hydrolyzed during its storage.